Geist Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Geist Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Geist Reservoir today is 21.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.
Water Temperature Chart Over the Last 30 Days
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 2 | 18.2°C | 19.0°C | |
| JUN 3 | 17.3°C | 19.0°C | |
| JUN 4 | 18.9°C | 19.0°C | |
| JUN 5 | 19.7°C | 19.0°C | |
| JUN 6 | 20.1°C | 19.0°C | |
| JUN 7 | 20.9°C | 19.0°C | |
| JUN 8 | 21.1°C | 19.0°C | |
| JUN 10 | 19.0°C | 21.7°C | |
| JUN 11 | 19.0°C | 21.5°C | |
| JUN 12 | 19.0°C | 21.4°C | |
| JUN 13 | 19.0°C | 21.2°C | |
| JUN 14 | 19.0°C | 21.1°C | |
| JUN 15 | 19.0°C | 21.0°C | |
| JUN 16 | 19.0°C | 20.8°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 0°C | 4°C | 8°C |
| February | 0°C | 4°C | 8°C |
| March | 2°C | 6°C | 11°C |
| April | 9°C | 13°C | 17°C |
| May | 12°C | 17°C | 21°C |
| June | 14°C | 19°C | 24°C |
| July | 18°C | 25°C | 32°C |
| August | 21°C | 26°C | 30°C |
| September | 19°C | 24°C | 29°C |
| October | 17°C | 21°C | 24°C |
| November | 7°C | 12°C | 16°C |
| December | 3°C | 6°C | 8°C |
Geist Reservoir: Water Temperature by Location
Geist Reservoir: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Geist Reservoir, a man-made impoundment northeast of Indianapolis, experiences pronounced seasonal shifts in surface water temperature. In spring the surface usually ranges from about 45–65°F (7–18°C) as the lake warms, while summer afternoons commonly see surface temperatures between roughly 75–85°F (24–29°C), and occasional spikes into the upper 80s (around 31–32°C) during heat waves. Early fall typically cools to the mid-60s to mid-50s°F (18–13°C) as stratification breaks down, and winter surface values often fall near freezing, roughly 32–40°F (0–4°C), with ice forming in colder years. Deeper water remains colder year-round and the reservoir can stratify in summer, so surface readings are the most relevant for swimmers.
Swimming itself is generally possible in Geist Reservoir, but there are few formal, lifeguarded public beaches and much of the shoreline is private or occupied by docks and marinas. Local rules and property ownership can limit access, and safety concerns—high boat traffic, submerged structures, aquatic vegetation and occasional water-quality advisories—mean swimmers should choose locations carefully, heed posted notices, and avoid busy boating areas. In short, the water temperatures become comfortable for recreation in mid to late summer, but access and safety considerations determine whether swimming is advisable at any specific spot.